Garments having durable antistatic properties

ABSTRACT

A GARMENT HAVING DURABLE ANTISTATIC PROPERTIES AND COMPRISING AN OUTSIDE FABRIC AND A LINING OR INTERLINING FIBROUS MATERIAL, AT LEAST A PART OF WHICH CONTAINS AT LEAST ABOUT 0.01% BY WEIGHT OF AN ELECTRICALLY CONDUCTIVE FIBER, SAID ELECTRICALLY CONDUCTIVE FIBER COMPRISING A SUBSTRATE OF CHEMICAL FIBER AND AN ELECTRICALLY CONDUCTIVE COATING THEREON, AND SAID ELECTRICALLY CONDUCTIVE FIBER HAVING THE FUNCTIONAL PROPERTIES OF TEXTILE FIBERS.

United States Patent 3,582,448 GARMENTS HAVING DURABLE ANTISTATIC PROPERTIES Tomomi Okuhashi, Tokyo, and Kinichi Kumura,

Amagasaki-shi, Japan, assignors to Teijin Limited,

Osaka, Japan No Drawing. Filed Feb. 19, 1969, Ser. No. 800,769

Claims priority, application Japan, Apr. 23, 1968,

IS/33,281; June 18, 1968, 43/51,394; July 27, 1968, 43/64,373; Sept. 25, 1968, 43/83:,122

Int. Cl. 1332b 5/16, 27/20 U.S. Cl. 161-87 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to garments having durable antistatic properties.

Generally, garments consisting of organic textile fibers have an undesirable property of becoming charged with static electricity on being subjected to friction, particularly at low humidity. Woven or knitted goods made of hydrophobic chemical fibers such as synthetic fibers, for instance, polyamides, polyesters, polyacrylonitriles and polyolefins, and semi-synthetic fibers, for instance, acetate and triacetate fibers tend to be electrostatically charged, and undergo such troubles as the occurrence of sound of electrostatic discharge, clinging of these goods to a human body and electric shock.

As an attempt to overcome this difiiculty, U.S. Pat. 3,288,175 discloses the incorporation of a small quantity of metallic fibers into woven goods. According to this patent, it is necessary to use a metallic fiber having as fine a denier as possible. Because the metallic fibers are essentially dilferent in nature from ordinary textile fibers, these two kinds of fibers are hardly compatible with each other. Therefore difiiculties are encountered in the steps of mixing metallic fibers of fine denier with textile fibers, spinning, weaving, processing, dyeing and finishing, and the hand of the obtained woven materials is not good. In addition, it is difficult to manufacture metallic fibers of fine denier, and the metallic fibers are expensive.

As another method of overcoming these difiiculties, Japanese patent application publication No. 4,196/ 57 and US. Pat. 2,845,962 disclose a method of preventing electrostatic charge of woven goods by incorporating into textile fibers electrically conductive fibers with carbon black dispersed throughout their interior. In order, however, for the electrically conductive fibers containing carbon black to have the desired electric conductivity, they must contain carbon black in a great quantity, i.e. at least 25% by weight. Moreover, because of low mechanical strength, these fibers tend to be broken in the steps of spinning, weaving and processing.

The present invention has made it possible to solve the aforesaid problems by making garments with the use of a lining or interlining fibrous material comprising organic textile fibers and an electrically conductive fiber.

According to the present invention, there is provided a garment comprising an outside fabric and a lining or interlining fibrous material, characterized in that at least a part of said lining of interlining fibrous material contains at least about 0.01% by weight of an electrically conductive fiber, said electrically conductive fiber comprising a substrate of chemical fiber and an electrically conductive coating thereon, and said electrically conductive fiber having the functional properties of textile fibers.

The term fiber used herein and appended claims, unless otherwise specified, includes both staple fibers and continuous filaments.

The term outside fabric used herein and appended claims, unless otherwise specified, means a fabric on the right side of a garment. The term lining fibrous material means a fabric on the reverse side of the garment, and the term interlining fibrous material means a fabric or fiber interposed between the fabrics of the garment.

The electrically conductive fiber to be incorporated into a lining or interlining fibrous material for garments according to the invention comprises a substrate of chemical fiber and an electrically conductive coating formed thereon, and has the functional properties of textile fibers.

By the term functional properties of textile fibers used herein is meant, in general, the possession of mechanical properties by which a fiber can be subjected to the usual spinning, twisting, crimp-imparting, weaving and knitting operation and can stand such conditions which a fiber usually encounters during these processing steps as well as during its use, i.e. Such conditions as abrasion, tensile stree, bending stress, repetitive flexure, repetitive elongation and relaxation, and repetitive compression and relaxation; and the possession of compatibility and coprocessability with the usual organic textile fibers. The electrically conductive fiber to be used in the lining or interlining fibrous material according to the present invention should possess mechanical properties which are about comparable to those of the substrate of the chemical fiber. It should generally possess a tensile strength of at least about 1 g./den., preferably at least about 2 d./gen., an elongation at break of at least about 3%, preferably about 10%, and an initial modulus not exceeding about 3000 kg./mm. preferably not exceeding about 2000 kg./mm. The electrically conductive fiber used should preferably possess not only the foregoing mechanical properties along the longitudinal direction but also its mechanical properties along the lateral direction such as flexibility and also its chemical properties such as its property to withstand the usual scouring, dyeing and washing operations. In addition, the electrically conductive fiber to be used in the present invention should generally possess a low density of less than 2.5 g./cc., and preferably a low density of less than 2.0 g./cc.

The electrically conductive coating can be formed on the substrate fiber in the following manner. For example, a polymeric binder solution or emulsion which contains dispersed therein finely divided silver, gold, platinum, copper; brass, nickel, aluminum, tungsten or other finely divided metals as well as other finely divided electrically conductive materials such as copper oxide or carbon black is applied to the surface of the substrate fiber, after which the coating is dried and, if desired, the polymeric binder is cured. Alternatively, the conductive coating of metals such as nickel, copper, cobalt, chromium, zinc, tin or others can be formed on the substrate fiber by chemical plating. The coating of metals such as aluminum, copper or others on the substrate fiber can also be formed by vacuum evaporation. Further, if necessary, a top coating of an organic polymer may also be applied on to the surface of the electrically conductive coating. The electrically conductive fiber to be used in the present invention preferably is one having an electrical resistance not exceeding about 2000 megohms per centimeter.

As the chemical fiber used as the substrate of the electrically conductive fiber, of linear synthetic polyamides such as nylon 6 and nylon 66 are preferably, from the standpoint of mechanical properties and adhesiveness to the electrically conductive coating. Also from the standpoint of mechanical properties, fibers of polyesters such as polyethylene terephthalate are preferable. But fibers of other synthetic polymers can also be used such as those of polyolefinic polymers, acrylic polymers, polyvinyl acetal, polyureas, polyimides and blends thereof and cellulosic fibers composed of cellulose acetate or regenerated cellulose. The fineness of fibers is usually about to 50 denier, preferably about 10 to denier. Furthermore, the chemical fibers used as the substrate may be either in the form of monofilament or multifilament.

The electrically conductive coating can be formed on the substrate fiber in the following manner. A solution or an emulsion of a binder polymer which contains dispersed therein finely divided metals, for example, silver, gold, platinum, copper, brass, nickel, aluminum, tungsten, as well as other finely divided electrically conductive materials such as copper oxide and carbon black is applied to the surface of the substrate fiber, following which the coating is dried and, if desired, the binder polymer is cured. As the electrically-conductive finely divided powder, finely divided powders of silver and carbon black are especially preferable in view of resistance to scouring, dyeing, washing, and chemicals and in view of electrical conductivity.

Usable as the binder polymers are various synthetic resins such as acrylic, epoxy, phenolic, urethane, melamine, urea, polyester, vinyl and silicone resins, natural and synthetic rubbers, and mixture of these. However, in each individual case, choice should be suitably made, taking into consideration the characteristics of binders such as their adhesiveness to the substrate fiber, the abrasion resistance and chemical resistance of the coating, and flexibility of the coated substrate fiber. Further, this liquid composition can be incorporated with a thickening agent, an anti-oxidant, a modifier for imparting flexibility to the coating, a curing agent for the binder polymer as well as other additives. As examples of suitable binder polymers, included are the combinations of the oil-soluble phenolic resins with chloroprene polymer, styrene/butadiene copolymer, acrylonitrile/butadiene copolymer and other synthetic rubbers; the combinations of a bisphenol/ epichlorohydrin type epoxy resin having an epoxy equivalent of about 170 to 250 with a polyamide resin, an epoxidized vegetable oil or liquid polyalkylene sulfide; a relatively low molecular weight polyurethane urea having terminal N,N-disubstituted ureylene groups; the combination of partially saponified vinyl chloride/vinyl acetate copolymer and a melamine resin modified by n-butanol; and the combination of ethyl acrylate/styrene/hydroxyethyl acrylate copolymer with a melamine resin modified by n butanol.

The electrically conductive fibers used in the invention should have an electrical resistance not exceeding of about 2000 megohms per centimeter, because if the electrical resistance exceeds this limit, the garments having antistatic properties as contemplated by the invention cannot be obtained. To manufacture electrically conductive fibers having an electrical resistance not exceeding of about 2000 megohms per centimeter, it is necessary to adjust the amount of finely divided powder of an electrically conductive material present in the electrically conductive coating, and the thickness of the coating.

In order to attain an electrical resistance not exceeding about 2000 megohms per centimeter, the content of electrically conductive material in the coating must generally be at least 50% by weight, preferably at least by weight when it is a metal such as silver, whereas its content must be at least 5% by weight, preferably 10% by weight when it is carbon. Further, it is preferred, from the standpoint of stable conductivity, that the thickness of the coating should be at least about 0.3 micron in the case of finely divided metals, and at least about 0.5 micron in the case of carbon. On the other hand, the upper limit of the thickness of the electrically conductive coating and the upper limit of the amount contained in the coating of the finely divided particles of the electrically conductive material are restricted in actual use in view of the above mentioned properties as the textile fiber, i.e., the functional properties as the textile fiber such as mechanical properties of the fiber and flexibility. A coating of excessive thickness is not only unnecessary from the standpoint of conductivity but also undesirable especially from the standpoint of flexibility. A coating containing finely divided metals as its electrically conductive material, dispersed in a polymeric binder matrix, should have an average thickness not exceeding about 10 microns, prefferably not exceeding about 5 microns. It is further necessary that a coating containing carbon should have an average thickness not exceeding 15 microns, preferably not exceeding 10 microns. Again, coatings containing the finely divided metals in an amount exceeding about 90% by weight or the carbon in an amount exceeding about 60% by weight are in general poor in their tenacity and their adhesiveness to the substrate and hence easily tend to become separated from the substrate during the processing steps and in use.

Another desirable type of electrically conductive fiber that is used in the lining or interlining fibrous material for garments according to the present invention comprises a substrate of chemical fiber and a metallic coating of an average thickness not exceeding about 1.5 micron which has been chemically deposited on the former, the so made up fiber having an electrical resistance of less than about 2000 megohms per centimeter and the functional properties of textile fibers. The method of manufacturing an electrically conductive fiber of this kind comprises chemical plating of the substrate fiber with a metal. As the substrate fibers, in this case, particularly to be preferred from the standpoint of ease of application of the metallic coating and their ability to adhere metals are those of acrylic polymer in which the content of acrylonitrile is at least mol percent and those of polyester whose content of ethylene terephthalate is at least 80 mol percent. The substrate fiber can have a textile denier of about 1-50 denier.

The metallic coating can be applied to the substrate by the method which per se is known for chemical plating of organic polymeric materials, optionally followed by electroplating. Chemical plating can be carried out on substrate fibers of multifilament, monofilament or staple form. In carrying out the chemical plating of shaped articles such as cast articles of organic polymeric materials, the general practice is to perform such pretreatments as mechanical roughening, degreasing, etching, sensitizing and activation of the surface. The step of mechanically roughening the surface is performed with a view to form a rough surface suitable for performing the metallic plating, but in the case of a substrate of fiber form, this step is not particularly necessary, since the surface of the fiber is roughened to a suitable extent to be already convenient for carrying out the metallic plating operation. When the acrylic fiber is to be used as the substrate, a satisfactory metallic coating can be formed on the substrate even though the etching step is omitted. The etching of the polyester fibers is best carried out with an alkali to an extent that a weight decrease of 0.3 to 10% by weight takes place. As the etching solutions the aqueous or alcohol solutions of such alkalis as sodium hydroxide, potassium hydroxide and sodium carbonate may be used, but the use of the aqueous sodium hydroxide solution is especially to be desired. The polyester fibers are dipped in such an alkaline bath, and the concentration and temperature of the bath and the time of immersion are suitably chosen such that the decrease in weight due to dissolution comes within the range of 0.3- 10%. For example, in the case where an aqueous sodium hydroxide solution is used, the end can be fully achieved by treating the degreased polyester fiber for 3 seconds 30 minutes at 50-100 C. using a bath whose concentration is 05-30% by weight. The substrate fiber, which has thus received the chemical treatment, is then waterwashed or water-washed after having been neutralized with a dilute acid solution, and thereafter delivered to the next step. The degreasing, sensitizing and activation steps can be carried out in accordance with the wellkno-wn procedures for applying chemical plating to the shaped articles of organic polymers.

The chemical plating is carried out on the pretreated substrate. As examples of metals suitable for chemical deposition on the substrate, there are nickel, copper, cobalt, chromium, zinc and tin, or which nickel is of advantage from the standpoint of ease of plating and economy. As the composition of the chemical nickel plating bath, several types can be mentioned, such as soluble nickel salt-hypophosphite, soluble nickel salt-boron nitrogen compound, and soluble nickel salt-urea. While basically any of these compositions can be used with satisfaction, convenient is the bath whose composition is of the soluble nickel salt-hypophosphite type, and particularly preferred is that of this type which is acidic. An excellent electrically conductive fiber can be obtained with a very short period of treatment by the use of a relatively high plating bath temperature. For example, when an acidic plating bath consisting predominantly of 20 grams per liter of nickel sulfate, 24 grams per liter of sodium hypophosphite and 27 grams per liter of lactic acid, whose pH has been adjusted to 5.6 is used, satisfactory treatment is obtained with a plating bath temperature of 60- 98 C. and a treatment time of seconds-9 minutes. Particularly, if the treatment is carried out at a plating bath temperature of 8090 C., a fiber excelling in conductivity can be obtained satisfactorily even with a treatment time of less than one minute. Since, as hereinbefore described, the chemical nickel plating can be carried out under treatment conditions requiring a very short period of time, it is especially convenient to use it in the continuous chemical plating of filaments. The metallic coating which has been chemically deposited on the substrate fiber can, if desired, be increased in its thickness .by further deposition of metal thereon by electroplating. The metal to be electroplated may be one which is the same as that was chemically plated or one differing therefrom.

The thickness of the metallic coating formed on the substrate fiber must be controlled so as to ensure that the product retains the functional properties of textile fibers. A metallic coating of excessive thickness results in a product having poor mechanical properties, e.g. elongation and flexibility, and is also unnecessary from the standpoint of conductivity. The upper limit of the average thickness of the metallic coating depends upon the class and denier fineness of the substrate fiber, the class of metal, and the use to which the final product is to be put, but in most cases it should not exceed 1.5 micron. On the other hand, the lower limit of the average thickness of the metallic coating may sufiiciently be one which will render the fiber conductive. It was found that there were frequently discontinuities in the metallic coating whose average thickness was less than 0.001 micron and, as a result, that the coated product frequently did not have a conductivity of satisfactory stability. Hence, it is preferable to control the average thickness of the metallic coating to within the range of 0.01 to 1.5 micron, and particularly 0.1 to 0.5 micron.

A top coating of an organic polymeric material can be applied to the electrically conductive fiber. It is to be particularly preferred in the case of the electrically conductive fiber having a metallic coating manufactured by chemical plating or vacuum evaporation coating that a top coating be applied to protect the metallic coating from being oxidized and corroded as well as peeling off from the substrate. While the application of a top coating to an electrically conductive fiber having an electrical resistance of less than about 2000 megohms per centimeter imparts an electrical resistance of the order of several thousand megohms per centimeter to the fiber, it was surprisingly found that a fiber having a high resistance such as this could be effectively used for achieving the objects of the present invention provided that the starting electrically conductive fiber was one possessing an electrical resistance of less than about 2000 megohms per centimeter. As the organic polymeric material to be applied, preferred are the synthetic rubber type polymers which excell in their adhesiveness to metal and the waterrepellent silicone resin type polymers, but others can also be used.

The lining or interlining fibrous material for use in garments according to the invention consists of organic textile fibers and a minor amount of said electrically conductive fibers. For achieving notable antistatic effects, the electrically conductive fiber must be present in the lining or interlining fibrous material in an amount of at least 0.01% by weight. Although it is possible at times to achieve the antistatic efiFects even with smaller amounts than indicated above, the effects are frequently not stable. When the electrically conductive fiber is incorporated at the ratio of about 1% to about 2% by weight, the degree of improvement in the antistatic effects corresponding to the increase of the electrically conductive fiber gradually decreases as the ratio approaches the latter value. Hence, the use of the electrically conductive fiber in an amount in excess of about 2% by weight is unnecessary for practical purposes. Therefore, from a practical standpoint, the electrically conductive fiber may be preferably incorporated in the lining or interlining fibrous material at the ratio of about 0.01% to about 2% by weight, and preferably about 0.02% to about 1% by weight.

The electrically conductive fiber can be incorporated in a lining or interlining fibrous material for garments by staple fiber blend, mix spinning, doubling, mix twisting, mix weaving, mix knitting and other optional means. Generally, an electrically conductive yarn containing an electrically conductive fiber is prepared from the electrically conductive fiber and an ordinary organic textile fiber. It is convenient to prepare a lining or interlining fibrous material by using only the electrically conductive yarn or to prepare it from the electrically conductive yarn and an ordinary weaving or knitting yarn, which is not electrically conductive, by an ordinary mix weaving or mix knitting. Depending upon the applications of a final product, it is possible to produce the intended lining or interlining fibrous material by mix weaving or mix knitting of an electrically conductive spun or filamentary yarn consisting only of electrically conductive fibers with an ordinary weaving or knitting yarn, which is not electrically conductive. It is also possible to produce the intended lining or interlining fibrous material by adhering or sewing electrically conductive fibers to a lining or interlining fibrous material consisting of an ordinary organic textile fiber.

It has been found that it is advantageous and preferable to incorporate the electrically conductive fiber in the form of continuous filaments. For instance, when the knitting or weaving yarns are spun yarns, the incorporation of electrically conductive fibers can also be effected by using spun yarns containing electrically conductive fibers as part of these knitting or weaving yarns. Even when the knitting or weaving yarns are spun yarns, it is advantageous to use electrically conductive fibers in the form of continuous filaments and to associate them with separately produced spun yarns, which are not electrically conductive. One advantageous method of producing a lining or interlining fibrous material for garments according to the invention includes conducting weaving or knitting while paralleling continuous electrically conductive filaments, advantageously paralleling one electrically conductive monofilament, with part or whole of weaving or knitting yarns, which are not electrically conductive, to be made into the lining or interlining fibrous material. It has been confirmed that a more excellent and more stable antistatic effect can be obtained by incorporating the electrically-conductive fibers in the form of continuous filaments than in the form of staple fibers. As a matter of course, the form of continuous filament is more advantageous for producing such an antistatic fibrous material. Especially when weaving or knitting yarns are continuous filaments, it is also possible to associate an electrically conductive filament in the form of at least one, advantageously one, monofilament with an ordinary organic textile filament bundle, subjecting them to a mechanical crimping, and to use them as a part or whole of the weaving or knitting yarns.

It was unexpected that the electrically conductive filament as used in the present invention could stand twisting, crimp-imparting, weaving and knitting.

The garment of the invention comprises an outside fabric and a lining or interlining fibrous material, and at least a part of said lining or interlining fibrous material contains an electrically conductive fiber in the above-mentioned amount.

The garment of the invention may be produced by using an outside fabric consisting of ordinary organic textile fibers and a lining and/or interlining fibrous material containing electrically conductive fibers. It can also be produced by using an outside fabric consisting of ordinary organic textile fibers and a lining cloth containing electrically conductive fibers, the latter being bonded to the former by an adhesive or foam. In this instance, various woven goods, knitted goods, laces and nettings can be used as the outside fabric. The garment of the invention can also be made of a fabric consisting of ordinary textile fibers with one or more electrically conductive fibers interposed in the fold-back portion of the garment. In this case, the electrically conductive fibers may be interposed alone or together with other fiber.

Garments such as suits, trousers, skirts, waist coats, rain coats, over-coats, and Japanese kimonos which have been made of a cloth containing the electrically conductive fibers as a part or whole of the lining hardly undergo electrostatic charge, and such electrostatic troubles as the clinging of garments to the wearer, soiling owing to attraction of dust, and the sound of electrostatic discharge at the time of undressing can be reduced to a remarkable extent. This antistatic effect depends on an amount of said cloth or an amount of the electrically conductive fibers to be incorporated in the cloth. If the electrically conductive fibers or yarns containing them are arranged at intervals of less than 30 cm., preferably less than 10 cm., in the lining material, the electrostatic troubles can be effectively reduced in and around those portions where the above-mentioned lining material has been applied by sewing. For instance, a suit containing a lining cloth having electrically conductive fibers at intervals of cm. in parallel relationship to each other does not cling to the wearer and does not issue a sound of electrostatic discharge, at the time of dressing and undressing, and the soiling of the suit is remarkably reduced. A remarkable antistatic effect is exhibited when said cloth is used as a lining at a portion which tends to be subjected to friction. For instance, when the above-mentioned cloth is used as a lining at knee portions of trousers, clinging of the trousers to the wearer does not occur. If it is used as a lining at the bottom of a skirt, its clinging to the wearer does not occur and there is less soiling.

The garment of the present invention made by using a material containing electrically conductive fibers as a part or whole of interlining cloth between an outside fabric and a lining is subjected to the occurrence of static electricity owing to friction to a lessor extent, and therefore is far more free from such electrostatic troubles as soiling owing to attraction of dust, clinging of the garment to the wearer, and the sound of electrostatic discharge. This antistatic effect depending on an amount of such interlining cloth and an amount of the electrically conductive fibers contained therein. For instance, when a material containing about 0.1% by weight of the electrically conductive fibers is used as an interlining cloth at the collar and cuff portions of a tricot shirt made solely of polyester fibers, the generation of static electricity at these parts is remarkably reduced, and the soiling of these portions is remarkably reduced.

A bonded fabric or cloth made by bonding a lining of a fabric containing or consisting of electrically conductive fibers to an outside cloth by means of an adhesive or foam has an excellent antistatic effect. Garments made of this bonded fabric are subjected to the occurrence of static electricity owing to friction to less extent, and therefore is far more free from such electrostatic troubles as clinging of the garments to the wearer, soiling owing to attraction of dust, and the sound of electrostatic discharge.

Garments in which electrically conductive fibers are present in their fold-back portions are almost free from the occurrence of static electricity, and such static troubles as the sound of electrostatic discharge, attraction of dust, and unnatural creases or clinging are greatly reduced. The electrically conductive fibers are retained between the fabrics, and do not appear on the surface. Therefore, the outer appearance of the product remains the same.

The electrically conductive fibers used in the present invention include not only those in which an electric resistance is in the region of an ordinary conductor, but also those in which an electric resistance is as high as 2000 megohms per centimeter. It is surprising that a marked antistatic effect is exhibited even when a small amount of a fiber having such high electric resistance is incorporated. It is not easy to explain the mechanism of prevention of electrification with simplicity. Generally, a high voltage above 1000 volts poses a problem in an unfavorable electrification of ordinary organic textile fibers, and a quantity of electrostaticity generated at this time is very small. Hence, it is presumed that even in the case of such high electric resistance, a local intrinsic electric breakdown of the coating occurs under such high voltage, and electrostatic charge is easily dissipated with this electrically conductive fiber by such efiects as gaseous corona discharge, surface flashover and tracking and leakage, thus preventing the accumulation of electrostatic charge. This seems to contribute greatly to the prevention of electrostatic charge. Further, the dispersion of electrostatic charge through the electrically conductive fiber as well as the shielding effect of the fiber seem to contribute to the antistatic effect.

The electrically conductive fibers used in the present invention retain the tfuncional properies of textile fibers and have durability against various conditions that are usually encountered during the manufacture of the lining or interlining fibrous material for use in garments and during its use, such as abrasion, repetitive fiexure, repetitive elongation and relaxation, scouring, dyeing and washing. The electrically conductive fibers of this invention can be incorporated in the lining or interlining fibrous material very readily during their manufacture. The lining or interlining fibrous materials according to the present invention which contain a small amount of the electrically conductive fibers have durable antistatic properties, and their appearance and hand are also highly satisfactory. Further, these electrically conductive fibers are compatible with the other fibers that make up the fabric, and therefore, their tendency to separate from the surface during the use of the fabric is slight.

The following examples are given for further illustration of the invention. The resistance of the electrically conductive fiber shown in the examples was determined by using an FM tester, Model L-l9-B and an automatic insulation-ohrnmeter, Model L-68, manufactured by Yokogawa Electric Works, Japan, and breakage tenacity, breakage elongation and initial Youngs modulus were measured using a sample of cm. of gauge length with a stretching speed of 5 cm./min. The value of the electrification voltage was measured by means of a collecting type potentiometer, Model K-325, manufactured by Kasuga Electric Company, Japan. The content of the electrically conductive fiber is presented in percentage by weight of the electrically conductive fiber based on the organic textile fiber which constitutes the lining or interlining fibrous material.

Unless otherwise specified, the parts and percentages of composition in the examples are on a weight basis.

EXAMPLE 1 -denier nylon 6 monofilament was immersed in and passed at a rate of m./min. through a paste obtained by well mixing 100 parts of flaky fine powder of silver (having an average diameter of 1.5a), 100 parts of an adhesive of the nitrile rubber-phenol type (having a solid content of 24% and 5 parts of methyl isobutyl ketone. The monofilament was passed through a slit to adjust its coating thickness, and then passed through a hot air drier at 120 C. for 6 seconds. Subsequently, it was further passed through an air bath at 195 C. for 6 seconds. An electrically conductive monofilament having an electrical resistance of 120 .Q/cm. and an average thickness of the electrically conductive coating of 2.3,u. was obtained.

This electrically conductive filament has a tenacity at break of 3.3 g./den. (5.6 g./den. calculated as the substrate fiber), an elongation at break of 43% and an initial Youngs modulus of 250 kg./mm. and has a tenacity, pliability and flexibility much the same as those of the substrate filament. Also, it is light in weight with a density of about 1.6 g./ cc.

In obtaining a plain weave cloth consisting of 50 denier/24 filament polyethylene terephthalate multifilaments as warps and wefts, one electrically conductive filament was doubled with the multifilaments, and the resulting filaments bundles were arranged in Warp and weft directions at intervals of 1 cm., 3 cm., 5 cm., and 10 cm.

in the plain weave cloth were 0.64%, 0.21%, 0.13%, and 0.06%, respectively.

Two skirts having a lining all over the back side were made using a cloth consisting of polyethylene terephthalate fibers containing no electrically conductive fibers as an outside fabric and the plain weave cloth containing the electrically conductive fibers above obtained as well as a plain weave cloth containing no electrically conductive fibers as a lining. The skirts were subjected to drycleaning for 6 minutes with perchloroethylene contain ing 1% surface active agent. The following wearing and undressing test was conducted at a temperature of 25 C. and at 27% RH wearing a slip made of nylon underneath. When the wearer put on the skirt which contained no electrically conductive fiber, and rubbed it vigorously, it clung tightly to the wearers body, giving the wearer a pressing feel and also presenting a disagreeable appearance. The electrification voltage of the skirt after undressing was as high as 22 kv. On the other hand, the skirt containing the electrically conductive fibers hardly showed such electrostatic troubles, and the electrification voltage of the skirts after undressing was also very much reduced. It was found that the skirts made using lining clothes containing the electrically conductive filaments arranged at intervals of 1 cm., 3 cm., 5 cm., and 10 cm. respectively showed an electrication voltage of only 2, 2, 2.5 and 3 kv.

Even when these skirts were subjected to drycleaning 20 times, their antistatic effect was hardly lost, showing an excellent durability.

EXAMPLE 2 (A) A 15-denier nylon-6 monofilament was passed through a paste consisting of a mixture of finely divided flaky silver having an average particle size of 1.5 microns and a nitrile rubber-phenol type adhesive (solid content 24%) in the ratio respectively as indicated in Table A, at a feed rate of 25 m./min., and then passed through a slit to adjust its coating thickness. Thereafter, the monofilament was passed through a hot air oven at C. for 6 seconds, and then through an air bath at 190 C. for 6 seconds. An electrically conductive monofilament having an electrical resistance indicated in Table A was obtained respectively.

(B) A 15 denier nylon-6 monofilament was passed through a paste consisting of a mixture of acetylene black and a nitrile rubber-phenol type adhesive (solid content 24%) in the ratio respectively as indicated in Table B, at a feed rate of 25 m./min., and then passed through a slit to adjust its coating thickness. Thereafter, the monofilament was passed through a hot air oven at 70 C. for 6 seconds, and then through an air bath at 190 C. for 6 seconds. An electrically conductive monofilament having an electrical resistance indicated in Table B was obtained respectively.

As shown in Tables A and B, all the obtained electrically conductive filaments possess properties as weaving and knitting fibers and retain tenacity, pliability and flexibility which hardly differ from those of the substrate fila- The ratios of the electrically conductive fibers contained 60 ment. In addition, they are light in weight.

TABLE A Properties of the electrically conductive filament Compounding rate Breakage of paste tenacity Thickness based on Finely Adhesive of the electhe denier divided (part trically of sub- Initial flaky calculated conductive Electrical Breakage strate Breakage Youngs Specific silver as solid coating resistance tenacity filament elongation modulus gravity (part) content) (micron) (Q/cm.) (g./d.) (g./d.) (percent) (kg/mm?) (g./cc.)

78 22 3. 8 2. 5X10 2. 6 5. 4 42 280 1. 7 8O 20 2. 3 1. 2X10 3. 3 5.6 43 250 1.6 80 20 1. 0 5. 0X10" 4. 2 5. 5 41 260 1.6 84 16 2. 0 8. 0X10 3. 3 5. 6 42 240 l. 6

TABLE B Properties of the electrically conductive filament Compounding rate Breakage of paste tenacity Thickness based on Finely Adhesive of the electhe denier divided (part trically of sub- Initial flaky calculated conductive Electrical Breakage strate Breakage Young's Specific silver as solid coating resistance tenacity filament elongation modulus gravity (part) content) (micron) (SI/cm.) (g./d.) (g./d.) (percent) (kg/mm?) (g./cc

Specimen No.:

13-1 15 85 7. 8. 0X10 3. 3 5. 3 38 240 1. 1 13-2 30 70 4. 3 3. 0X10 4. 0 5. 6 40 230 1. 2 B-3 30 70 2. 5 6. 0X10 4. 5 5. 5 42 210 1. 2 B-4 45 55 3.0 4. 0x10 4. 2 5. 5 41 220 1. 2

In the manufacture of a plain weave cloth wherein warps and wefts consist of 75 denier/ 36 filament polyethylene terephthalate yarns, each of the said electrically conductive monofilaments was doubled with 75 denier/ 36 ylene black, 80 parts of an acrylic ester type adhesive (emulsion type; solid content 42% 5 parts of an aqueous solution of melamine resin (solid content 50%) and a small amount of a catalyst was prepared.

filament polyethylene terephthalate multifilaments, and the Each of the so prepared pastes was coated using a resulting filament bundles were woven in so that they rotary roller on a 15-denier polyethylene terephthalate arranged at intervals of 2 cm. in the warp and weft direcmonofilament, and cured by heating with an infrared ray tions. The ratio of the electrically conductive filament lamp. Electrically conductive monofilaments (A) and incorporated into the plain weave cloth was 0.300.49% r (B) having the properties indicated in the following table for the electrically conductive filaments (A), and 0.26- were obtained respectively. 0.37% for the electrically conductive filaments (B). These electrically conductive filaments have the prop- Mens suits were made by using a blend of polyethylene erties indicated in the foregoing table, and have tenacity, terephthalate fibers and wool (blend ratio being 65/35) pliability and flexibility which are little different from and by using the clothes containing electrically conductive those of the substrate filament. Moreover, they are light in filament as well as a cloth containing no electrically conweight.

Properties of the electrically conductive filament Breakage Thickness tenacity of the based on elec- Electhe denier trically trical of sub- Breakage Initial conductive resist- Breakage strate elonga- Young's Specific coating ance tenacity filament tion modulus gravity (micron) (SI/cm.) (g./d.) (g./d.) (percent) (kg/mm?) (g./cc.)

Specimen No.:

A 1. 9 5. 0x10 3. 3 4. 9 24 860 1.8 B 3.5 2. 0 10 3. c 4. 5 21 760 1. 3

ductive filament all over the back side as lining. These suits were subjected to dry cleaning. A wearing and undressing test was conducted at a temperature of 20 C. and 20% RH wearing cotton shirt underneath. When the wearer with the suit containing no electrically conductive filament rubbed it hard with the shirt and then put it off, a violent sound of electrostatic discharge was heard and the wearer received a violent electric shock on touching such a conductive material as metal. The suit then showed an electrification voltage as high as 40 kv., and the wearers body, +9 kv. On the other hand, the suits containing the lining of the present invention showed an electrification voltage of only +4 to +5 kv., and the body of the wearer, -0.2 to 0.5 kv. The abovementioned electrostatic troubles were almost obviated, and a remarkable antistatic effect was exhibited in spite of a small amount of electrically conductive fibers incorporated. It was noted that both an electrically conductive filament having a very high electrical resistance such as specimen B-l and a well conductive filament, when incorporated, exhibited the same excellent antistatic eifect.

EXAMPLE 3 (A) A well mixed paste consisting of 100 parts of spherical fine powder of silver having an average particle size of 0.1 micron, parts of an acrylic ester type adhesive (emulsion type; solid content 42%), 2.5 parts of an aqueous solution of melamine resin (solid content 50%) and a small amount of a catalyst was prepared.

(B) A well mixed paste consisting of 15 parts of acet- After the above-mentioned electrically conductive monofilaments were repeatedly bended times with a bended angle of 90, their electrical resistance hardly changed. Furthermore, even after they were rubbed for 5 minutes by a nylon gear (rotation speed r.p.m.; module 3.61; the number of teeth 40) under a load of 0.33 g./den. calculated on the basis of the substrate fiber, there was little change in their electrical resistance, and the electrically conductive coating was not stripped off.

The above-mentioned electrically conductive filaments were doubled with a 85 denier/ 20 filament multifilament of rayon acetate to obtain electrically conductive yarns. By using these electrically conductive yarns and the ordinary yarn consisting of a 85 denier/20 filament multifilament, plain weave lining clothes of acetate filaments was produced in which yarns containing electrically filaments were arranged in warps at intervals of 5 cm. The ratio of the electrically conductive filament incorporated in the lining cloth was about 0.06% for specimen (A), and about 0.05% for specimen (B).

Japanese kimonos consisting of polyethylene terephthalate fibers were made by using the so obtained lining clothes at a bottom portion which tends to be subjected to friction. These kimonos and another kimono containing a lining cloth having no electrically conductive fibers were subjected to dry cleaning. A wearing and undressing test was conducted with these kimonos at a temperature of 23 C. and of 35% RH wearing underwear of nylon-6 underneath. The wearer with the kimono containing no electrically conductive filament rubbed it vigorously with 13 the nylon underwear. The bottom of the kimono clung to the legs, and the wearer found it diificult to walk smoothly. At the time of undressing, a violent sound of electrostatic discharge occurred, and the wearer received a violent electrical shock on touching a conductive material such as metal. The kimono then showed an electrification voltage of 50 kv., and the wearers body, +15 kv. On the other hand, the kimonos containing the abovementioned lining clothes of the invention showed an electrification voltage of only -4 to kv., and the wearers body, 1 to 2 kv. The above-mentioned electrostatic troubles were almost obviated, and a remarkable antistatic effect was exhibited in spite of a very small amount of electrically conductive filament incorporated.

EXAMPLE 4 Ten parts of acetylene black and 90 parts of chloroprene phenol type adhesive (polychloroprene/p-t-butylphenol-formaldehyde resin=100/ 45 solvent toluene; solid content 24%) were thoroughly mixed to prepare a paste. A plurality of S-denier nylon 6 monofilaments were paralleled as slightly spaced from each other, and simultaneously immersed in the paste while retained'in the paralleled state. Then the filaments were passed through a slit to adjust the coating thickness, and cured by heating while retained at the small intervals to prevent their mutual adhesion. Thus they were covered with electrically conductive coating. The filaments were bundled into one strand and taken up onto a winder, to provide an electrically conductive multifilament yarn having an average electrically conductive coating thickness of 1.2 microns, and an average resistance of 10 Mil/cm. per single yarn. This electrically conductive filament had a breakage tenacity of 4.5 g./ den. (5.4 g./ den. on the basis of the denier fineness of the substrate filament), a breakage elongation of 40%, an initial Youngs of 250 kg./mm. and a density of 1.2 g./cc.

This electrically conductive multifilament yarn was mixed with a polyethylene terephthalate tow in advance of preparing therefrom polyethylene terephthalate staple fiber for making a non-woven fabric, and subsequently the tow and the yarn were'together subjected to a crimper to be crimped, followed by cutting to the length of 76 mm., to obtain a staple fiber incorporated with the electrically conductive fiber of the invention. The so incorporated electrically conductive fiber showed crimpability similar to that of polyethylene terephthalate fiber, but still retained sufiicient electrical conductivity.

The so obtained staple fibers containing the electrically conductive fibers were subjected to a carding engine to produce webs. Several webs were superimposed, and set by an adhesive of an acrylic ester emulsion type to thereby produce a non-woven fabric. The ratio of the electrically conductive fibers contained in the non-woven cloth was 1%.

An overcoat consisting of a blend of polyethylene terephthalate fibers and wool (blend ratio being 65/35) was made by using this non-woven cloth as an interlining at shoulder portions and front of garment.

A wearing and undressing test was performed with said overcoat and an ordinary overcoat containing an interlining non-woven cloth of ordinary polyethylene terephthalate fibers at a temperature of C. and an RH of 40% with a wool sweater worn underneath. When the wearer put on the overcoat containing as an interlining cloth a non-woven fabric consisting of ordinary polyethylene terephthalate fibers, lightly moved his hands, and put it off, the overcoat issued a sound of electrostatic discharge and clung to wearer. The overcoat then showed an electrification voltage of ---48 kv. On the other hand, the overcoat containing the interlining cloth of the invention which had been incorporated therein the electrically conductive fibers exhibited an electrification voltage of only l0 kv., and the above-mentioned electrostatic trou- 'bles were almost obviated. It was recognized that a remark- 14 able antistatic effect was exhibited in spite of a very small amount of the electrically conductive fibers incorporated.

EXAMPLE 5 A IO-denier acrylic monofilament was subjected to chemical nickel plating to form an electrically conductive monofilament having an average thickness of nickel coating of 0.4 micron and an average electrical resistance of 110 fl/cm. This electrically conductive filament had a tenacity at break of 2.8 g./den. (3.6 g./den., calculated as the substrate fiber), an elongation at break 14%, an initial Youngs modulus of 1000 kg./mm. and a specific density of about 1.5 g./cc.

One electrically conductive monofilament was doubled with a 75 denier/ 36 filament multifilament to get an electrically conductive yarn. An interlining cloth (plain weave cloth) for mens shirts was produced by using the resulting electrically conductive yarn and a yarn consisting of said 75 denier/36 filament multifilaments, and arranging the former at intervals of 1 cm. in warp and Weft directions. The ratio of the electrically conductive filament incorporated was 0.06%.

In the production of a tricot shirt consisting of polyethylene terephthalate fibers, the so obtained interlining cloth was used at the collar portions, front of garment and cuff portions, and moreover, several electrically conductive filaments obtained in Example 1 were disposed along the whole fold-back portion at the bottom of the shirt.

The so obtained shirt and a tricot shirt consisting of polyethylene terephthalate fibers and containing no electrically conductive filament, which had been sewn in accordance with the usual specification, were washed. A wearing and undressing test was performed at a temperature of 23 C. and an RH of 30% wearing an underwear of polyvinyl chloride fibers underneath.

In the case of the shirt containing no electrically conductive filament, a violent sound of discharge was heard at the time of undressing, and the shirt clung to the wearer and flared at the bottom. The electrification voltage after undressing was as high as +50 kv. for the shirt, and 10 kv. for the wearers body. On the contrary, the shirt containing the electrically conductive filaments exhibited an electrification voltage of only +12 kv. under the same condition, and the wearers body showed an electrification voltage of only 4 kv. It was seen that the electrostatic troubles were greatly reduced.

EXAMPLE 6 A pair of trousers was made using a plain weave cloth of polyethylene terephthalate fibers as an outside fabric, and the plain weave cloth containing the electrically conductive filament obtained in Example 1 at intervals of 3 cm. as a lining at the knee portions.

A wearing and undressing test was conducted at a temperature of 24 C. and an RH of 38% with the trousers as well as another pair of trousers which contained no electrically conductive filament, wearing an underwear of polyvinyl chloride fibers underneath. When the wearer with the trousers containing no electrically conductive filament stamped vigorously times, the trousers clung to his legs. The trousers then showed an electrification voltage as high as +27 kv. at the knee portions. On the contrary, the trousers containing the lining of the invention hardly clung to the legs under the same condition, and the electrification voltage at the knee portions was only +4 kv. It is seen from this result that a very excellent antistatic effect was attained.

EXAMPLE 7 A bonded fabric was made by using a knitted fabric of nylon as an outside fabric and a plain weave cloth containing the electrically conductive filament obtained in Example 1 at intervals of 3 cm. as a lining.

Two skirts were made by using this bonded fabric and another bonded fabric consisting of a knitted fabric and a plain weave not containing electrically conductive filaments. A wearing and undressing test was conducted with these two skirts under the same conditions as in Example 1. The skirt which contained no electrically conductive filament clung tightly to the wearers body and exhibited an electrification voltage of -22 kv. after undressing. On the contrary, the skirt according to the invention hardly clung to the wearer, and exhibited an electrification voltage of only 2.5 kv. This indicates an excellent antistatic effect.

EXAMPLE 8 One electrically conductive filament obtained in EX- ample l was disposed along the whole fold-back portion at the bottom of a skirt consisting of polyethylene terephthalate fibers. A wearing and undressing test was performed at a temperature of 24 C. and an RH of 50% with this skirt as well as another skirt which contained no electrically conductive filament, wearing with a slip consisting of nylon-6 fibers underneath. When the wearer put on the latter-mentioned skirt and stamped 100 times repeatedly, the skirt clung to the legs, and showed an electrification voltage at the bottom of kv. after undressing. On the other hand, the first-mentioned skirt of the invention hardly clung to the legs of the wearer and showed an electrification voltage at the bottom of only 8 kv. after undressing. It is seen therefore that a very excellent antistatic efiect was exhibited.

What is claimed is:

1. A garment comprising an outside fabric and a lining fabric, wherein the outside fabric consists essentially of electrically non-conductive yarns and the lining fabric comprises electrically non-conductive'yarns and electrically conductive continuous filaments in an amount of 0.01 to 2% based on the total weight of the lining fabric, said electrically conductive continuous filament comprising a substrate of an organic synthetic filament of 550 denier and an electrically conductive coating formed thereon in a thickness of 0.3 to 10 microns, said coating consisting essentially of a polymeric binder matrix having finely divided silver dispersed therein in an amount of 50 to 90% by weight based on the weight of the coating.

2. The garment according to claim 1, wherein the lining fabric consists essentially of electrically non-conductive yarns and electrically conductive yarns, each of said electrically conductive yarns consisting essentially of an electrically non-conductive yarn and at least one electrically conductive continuous filament.

3. The garment according to claim 1, wherein the distance between adjacent electrically conductive filaments in the lining fabric is less than 10 cm.

4. A garment in accordance with claim 1 wherein said electrically conductive fiber has a tensile strength of at least about one gram per denier, an elongation at break of a least about 3% and an initial modulus not exceeding about 3000 kilogram per square millimeter.

5. A garment in accordance with claim I wherein said electrically conductive fiber has an electrical resistance of less than about 2000 megohms per centimeter.

6. A garment according to claim 1 wherein the outside fabricand the fabric lining are bonded together and take the form of a bonded fabric or cloth.

References Cited UNITED STATES PATENTS 3,446,658 5/1969 Rose 16187X 3,288,175 11/1966 Valko 139 425 3,198,659 8/1965 Levy 117-160X 3,014,818 12/1961 Campbell 117-160X 2,845,962 8/1958 Bulgin 3172.3X

FOREIGN PATENTS 1,346,500 1/1963 France 117A.S.

OTHER REFERENCES Harold H. Webber: Metal Fibers, Modern Textiles Magazine, v. 47, May 1966, pp. 72-75.

ROBERT F. BURNETT, Primary Examiner M. A. LITMAN, Assistant Examiner US. Cl. X.R. 

